Great Lakes Article:

The University of Minnesota Duluth has a new tool for exploring the past.

UMD's Large Lakes Observatory recently acquired an X-ray fluorescence core scanner to analyze lake bottom sediments, which contain clues to past climates and climate changes.

The $400,000 scanner is one of only six in the world and two in the United States -- the other at Woods Hole Oceanographic Institution in Massachusetts.

The Large Lakes Observatory received its device earlier this month.

"It's been running basically 24-7 since," said geological sciences professor Erik T. Brown.

The scanner is basically a large box, about 17 feet long and 30 inches high. In the middle, the X-ray device itself stands about 6 feet tall. Core samples up to 6 feet long are fed in one end, and, after passing beneath the X-ray tower, emerge from the other end.

As the sample passes through the scanner, the instrument can photograph it, X-ray it and determine its chemical composition.

Careful examination of the chemicals and fossils in sediment can reveal a record of past climates. A better understanding of past climates may unveil cycles that will allow researchers to better predict future changes.

Two main advantages of the X-ray device are the speed and detail at which it examines samples.

The device can make measurements at a resolution of 0.008 inch -- the thickness of the layer of sediments deposited over just a few months in a typical lake.

"Physically sampling material by hand at that kind of resolution is impossible," Brown said.

And X-ray testing doesn't destroy the samples, as physical sampling does.

The Large Lake Observatory is using the X-ray sampler to study cores from the Great Lakes, lakes in Central Asia and Lake Malawi in East Africa.

The observatory was part of a team that collected 2,044 feet of core samples from the bottom of Lake Malawi last year. The samples contain a record of climates dating back 1.5 million years -- 15 times older than previous records.

By chance, the Large Lakes Observatory received its X-ray sampler the same month it's hosting the 10th International Paleolimnology Symposium.

More than 250 scientists from around the world are in Duluth this week for the symposium, which runs through Thursday at the Duluth Entertainment Convention Center.

Paleolimnology is the scientific study of the history of lakes. The focus of the symposium is the impact of humans on the Earth's ecosystems.

Officials with the observatory are using the symposium as an opportunity to tell others about the X-ray scanner in hopes of forming research partnerships.

"This thing produces so much data it's overwhelming," Brown said. "We want it used as much as possible, and the way to do that is to have a lot of collaborations with other people."